Download Name: _____ Period: ______ Date: ________ EHS Pond

Name: ______________________________ Period: ______ Date: __________
EHS Pond Assessment
Essential Questions:

Is the retaining pond behind the HS sports fields healthy?

What are the interactions between biotic and abiotic factors in an
environment?

How do we know what we know in science?
Scenario: What if there were a land developer interested in purchasing the land
from the Lake Washington School District in order to build homes? The biology
teachers at Eastlake High School would argue against the sale of this land,
stating that the retaining pond provides one of a few remaining essential wetland
habitats for many species.
On the other hand, the land developers could argue that the retaining pond is not
a “healthy” habitat and therefore does not need to be preserved. The land
developers could instead provide money to the Discovery Wetland Mitigation
Project near Discovery Elementary in exchange for the opportunity to develop the
land behind EHS.
Your Task: You and your team are the scientists that will determine, through
investigation, whether or not the retaining pond behind Eastlake High School is
“healthy” and should be preserved. This will include:
 Designing a research experiment
 Collecting data over several days at the start of each class.
 Writing up a formal lab report that presents your findings.
(Question,Hypothesis,Materials,Procedure, data, data analysis)
Freshwater pH
Acid Rain
Acid rain is rain that has been made acidic by certain pollutants in the air. Acid rain is a type of acid
deposition, which can appear in many forms. Wet deposition is rain, sleet, snow, or fog that has become
more acidic than normal. Dry deposition is another form of acid deposition, and this is when gases and dust
particles become acidic. Both wet and dry deposition can be carried by the wind, sometimes for very long
distances. Acid deposition in wet and dry forms falls on buildings, cars, and trees and can make lakes acidic.
Acid deposition in dry form can be inhaled by people and can cause health problems in some people.
What is acidity?
Acidic and basic are two ways that we describe chemical compounds. Acidity is measured using a pH scale.
A pH scale runs from zero (the most acidic) to 14 (the most basic or alkaline). A substance that is neither
basic or acidic is called "neutral", and this has a pH of 7.
Sources of Acid Rain
Acid rain is caused by a chemical reaction that begins when compounds like sulfur dioxide and nitrogen
oxides are released into the air. These substances can rise very high into the atmosphere, where they mix
and react with water, oxygen, and other chemicals to form more acidic pollutants, known as acid rain. Sulfur
dioxide and nitrogen oxides dissolve very easily in water and can be carried very far by the wind. As a result,
the two compounds can travel long distances where they become part of the rain, sleet, snow, and fog that
we experience on certain days.
Human activities are the main cause of acid rain. Over the past few decades, humans have released so
many different chemicals into the air that they have changed the mix of gases in the atmosphere. Power
plants release the majority of sulfur dioxide and much of the nitrogen oxides when they burn fossil fuels,
such as coal, to produce electricity. In addition, the exhaust from cars, trucks, and buses releases nitrogen
oxides and sulfur dioxide into the air. These pollutants cause acid rain.
Acid Rain is Caused by Reactions in the Environment
Nature depends on balance, and although some rain is naturally acidic, with a pH level of around 5.0,
human activities have made it worse. Normal precipitation—such as rain, sleet, or snow—reacts with
alkaline chemicals, or non-acidic materials, that can be found in air, soils, bedrock, lakes, and streams.
These reactions usually neutralize natural acids. However, if precipitation becomes too acidic, these
materials may not be able to neutralize all of the acids. Over time, these neutralizing materials can be
washed away by acid rain. Damage to crops, trees, lakes, rivers, and animals can result.
Citations
"Acid Rain." United States Environmental Protection Agency. n.d.. United States Environmental Protection
Agency . 7 Oct 2007 <http://www.epa.gov/acidrain/education/site_students/whatisacid.html>.
environment: health of humans and ecosystems
Loss of Wetlands:
How are Bird Communities Affected?
By Robert Fletcher
An ActionBioscience.org original article
articlehighlights
Wetland bird populations are stressed due to:




devastating habitat loss throughout the world
human intervention, such as agricultural expansion
other factors, such as invasive species and climate change
lack of research data to improve management practices
more on author
October 2003
Loss of Wetlands:
How Are Bird Communities Affected?
By Robert Fletcher
Wetland
habitat loss is
substantial in
the U.S.
Over 20 states
have lost 50%
or more of
their original
wetlands.
95% of
today's
wetlands are
freshwater.
New Zealand
has lost over
90% of its
original
wetlands.
Habitat loss has occurred at devastating rates throughout the world
over the past two centuries. Yet these losses are not all equal, and
some environments have been affected more than others. Wetland
habitat in North America provides one such example. Throughout
much of the United States, wetland habitat loss has been
substantial:




Between 1780's and 1980's, the lower 48 states have lost
53% of the original wetland habitat, or about 104 million
acres.1
Twenty-two states have lost 50% or more of their original
wetlands, with California losing the largest percentage
(91%) and Florida losing the most acreage (9.3 million
acres).1
Most recent losses over the past two decades have been
primarily due to agriculture and urban development.2
Most recent losses have been in freshwater wetlands (98%),
and 95% of the remaining wetlands are freshwater (as
opposed to coastal marshes).2
This severe wetland loss is probably not isolated to the United
States. For example, in New Zealand only 8% of the original
wetlands remain.3 However, for most areas of the world, little
information exists on both wetland loss and the current status of
wetlands.3
People tend to
confuse
In some ways, this severe habitat loss is not entirely surprising.
wetlands with Public perception of wetlands was historically quite negative, with
swamps.
wetlands perceived as swampy wastelands hardly good for
anything.4 This view shaped wetland policy until the early twentieth
century when perceptions began to change slowly with the growing
concern about declining migratory bird populations.4 Yet we now
know that wetlands are key components in ecosystems, providing
many services such as:


Wetlands are
key
components in
ecosystems.



reducing erosion by potentially decreasing floodwater
velocity and volume5
preventing downstream flood attenuation by spreading
excess water flow in floodplains and shallow depressions5
improving water quality by removing nutrients and
absorbing sediment loads6 (this potential benefit is highly
dependent on the amount of time that water is retained
within wetlands7)
acting as nutrient sources for fish and other aquatic
organisms inhabiting downstream areas in riverine and
coastal situations8
providing habitat for a variety of wildlife, such as waterfowl,
amphibians, and insects (for example, the wetland
landscapes in the Prairie Pothole Region of the Midwestern
United States are thought to produce 50-75% of the total
continental duck production9)
Fortunately, a variety of recent U.S. federal and state programs
(e.g., the Wetland Reserve Program10) have increased wetland
protection and provided incentives for habitat restoration. But did
this protection come too late?
Long-term
data on
wetland birds
is sparse, but
some
evidence
points to
declining
populations.
Invasive
species have
contributed to
declines in
some species
of birds.
Climate
changes affect
wetland birds
by altering
water levels
Patterns and potential causes of wetland bird population
trends
Meanwhile, many migratory birds have experienced declines
throughout the United States. Evidence for bird declines has been
based primarily on the past 40 years; prior to the 1960's little data
exist for interpreting long-term trends. Data on wetland birds are
particularly sparse, yet some evidence indicates that this group
might indeed be experiencing population declines.11,12 What factors
are contributing to these declines? And what are the ramifications?



Habitat loss and fragmentation: Both the loss and
fragmentation (or "breaking apart") of wetlands can have
detrimental impacts on wetland bird populations by
influencing habitat use, reproduction, and survival.13
Invasive species: Some non-native plant species have
invaded wetlands, causing profound changes in wetland
structure, which could make those wetlands unsuitable for
some species of birds. For example, Purple Loosestrife
(Lythrum salicaria) has invaded many wetlands in the
midwestern United States, and avian diversity in Purple
Loosestrife dominated wetlands can be lower than diversity
in other wetland types.14
Global climate change: Climate can have particularly strong
effects on wetland structure if precipitation declines or
and habitat
structure.
Most wetland
bird data is
inconclusive,
but some
patterns
of change
have
emerged.
Agricultural
expansion has
negatively
affected
waterfowl.
Habitat
changes
disrupt bird
breeding
success.
Habitat loss
can increase
wetland birds'
vulnerability
to predators.
becomes more variable in the future. Although much
disagreement remains in projecting future changes in
precipitation, most models project global increases in
precipitation along with some regional declines (including
predicted declines for the Prairie Pothole Region of the
United States) occurring due to poleward shifts in rain
belts.15 Precipitation can affect wetland birds by altering
water levels and habitat structure within wetlands.16 Also, in
times of drought, climate can cause habitat loss because
smaller, shallower wetlands will become dry, effectively
changing into grassland or open habitat. This climatecaused habitat loss has been correlated with annual
variation in some wetland birds, including many
waterfowl.9,17
How can habitat loss influence wetland birds?
Habitat loss and fragmentation might be particularly important for
bird populations. While evidence has mounted for habitat loss and
fragmentation affecting bird populations using other habitats,
evidence for effects on wetland birds is limited. Most research in
wetlands has been inconclusive because of poor study design.13
However, a few patterns have emerged.


Bird abundance and habitat use: Some species, such as
Seaside Sparrows, may not use small wetlands or may
occur in lower densities than in larger wetlands.18,19 Other
species, such as Black Terns, may be less likely to settle in
landscapes with few wetlands.19 Wetlands that are relatively
isolated from other wetlands might also contain fewer
species.20 Another index of the relative amount of habitat
fragmentation is the amount of perimeter (or edge) of
wetland relative to its area. In Iowa, one third of the
examined species occurred in lower densities in wetlands
with more edge relative to its area.21 In addition, wetland
loss can make the remaining wetlands in the landscape less
suitable for some species. At a larger temporal scale,
wetland loss from agricultural expansion was negatively
correlated with annual abundances of some waterfowl,
including Mallards and Northern Pintails.17
Reproduction: Breeding success for some species can
potentially be lower near the perimeters (edges) of wetlands
than toward the interior of wetlands because many nest
predators cannot access deep water habitats within
wetlands.22 These patterns in nest predation not only occur
with habitat fragmentation but also with variation in
precipitation. During dry periods, wetlands can be more
easily accessed by nest predators, potentially resulting in
lower breeding success. Although lower breeding success
can occur as a function of water depth in wetlands, it
remains unknown if and how anthropogenic habitat loss
might further reduce breeding success in wetlands.

Survival: Fragmentation and habitat loss could also
influence survival of some wetland birds because some
predators, such as skunks, tend to forage near the edges of
wetlands.16,23 Yet the influence of habitat loss on survival
has not been well documented.
Patterns like these illuminate the importance of protecting
complexes of wetlands in fragmented landscapes. Yet some of
these influences are directly related to changes in habitat structure
within wetlands. For example, as wetland size increases, habitat
heterogeneity within wetlands tends to increase, leading to
potential increases in bird diversity.16 Likewise, the structural
Wetlands
management changes of habitat near wetland edges probably produce the edge
must take into effects observed in some wetland systems. However, other factors
account both influencing wetland birds, such as wetland isolation, are clearly
operating at larger scales. Understanding local factors will be
local and
important for managing and conserving individual wetlands, but
larger-scale
larger-scale perspectives will be critical for understanding and
factors.
managing populations in fragmented landscapes.
Why worry about wetland birds?
Birds play
critical roles
in wetland
systems.
If habitat loss is indeed having detrimental impact on wetland bird
populations, what implications might these impacts have? Birds
play critical roles in wetland systems by acting as herbivores,
predators and prey, and being facilitators for plant dispersal -- not
to mention providing aesthetic values for bird watchers and other
nature enthusiasts.

Birds act as
herbivores,
predators and
prey, as well
as facilitate
plant
dispersal.
Also, wetland
bird watching
is a gratifying
experience.



Most wetland birds are insectivorous during the breeding
season, foraging on aquatic invertebrates for themselves
and their young. Birds (including adults as well as eggs,
nestlings, and juveniles) act as prey for other vertebrates,
such as snakes, skunks, and mink.
Some wetland birds, such as Canada Geese, are also
herbivores, feeding on aboveground plant parts. Herbivory
by these species can have potentially strong impacts on
habitat structure, plant species composition, and primary
productivity in wetlands.7
Wetland birds could be acting as dispersal agents for many
wetland plants that do not use abiotic agents, such as wind,
for dispersal into new areas. The importance of birds as
dispersal agents will likely increase with loss and
fragmentation of remaining wetlands because of the ability
of birds to use landscapes at large scales.
Finally, birds provide great intrinsic value to wetlands and
other habitats. Birds play a highly visible role in wetland
ecosystems. Observing vast numbers of ducks using
wetlands during migration is a magnificent sight, as is
hearing the raucous sounds of yellow-headed blackbirds
singing to each other during the breeding season.
An answer: habitat restoration?
Restored
wetlands tend
to have lower
plant diversity
than natural
wetlands.
Restoration
strategies
must consider
whether or
not certain
plants depend
on birds for
dispersal.
Wetland
restoration
has
successfully
produced
habitat for
some bird
species.
Habitat restoration is typically considered the alteration of an
ecosystem back to its initial or pre-settlement state. Most wetlands
are restored by breaking drainage tiles, thus returning hydrology to
the system. However, areas are not typically replanted with
wetland species.24 A key factor for restoring wetland areas will be
determining which plant species are predominantly avian-dispersed
and which are predominantly dispersed by other means. Those
species that are not dispersed by birds might require more
intensive restoration strategies than current practices typically
entail. For example, recent comparisons of plant diversity and
composition in restored and natural wetlands found that restored
wetlands tend to have lower plant diversity than natural
wetlands.24 Differences in restored wetlands were consistent with
the hypothesis that differences were due to dispersal limitation.
Regardless of the dispersal agent required, reducing isolation of
wetlands by strategic planning or focusing on wetland complexes
will likely improve restoration strategies focused on both plant and
bird diversity.21
Restoration practices have undoubtedly produced habitat for some
species of wetland-breeding birds. Recent work suggests that bird
communities in restored wetlands can be similar to those found in
natural wetlands,25 and that bird communities in restored wetlands
have higher diversity and abundances than in habitats that were
previously restored.12 For example, much of the restoration efforts
in the midwestern United States has focused on restoring wetland
habitat from agricultural areas. Agricultural areas tend to have
lower diversity and abundances of breeding birds than restored
wetlands.12 Yet it is still unclear whether populations in restored
areas have high enough reproduction to make positive
contributions to populations.
Conclusion
Conclusion:
More research
is needed on
the interaction
between
wetlands &
their bird
populations so
the issues can
be addressed
effectively.
Public perceptions of wetlands have come a long way in the past
few decades, yet wetlands are still being lost throughout the
country. Habitat loss can directly impact birds using these areas by
potentially influencing bird abundance and habitat use,
reproduction, and survival. Habitat restoration is one of the only
potential answers in counteracting wetland loss, but it remains
unclear if and how restoration influences population dynamics of
wetland birds. In addition, we need a better understanding of the
ultimate roles birds play in these ecosystems to effectively address
ongoing wetland loss and the strategies focused on mitigating this
issue.
© 2003, American Institute of Biological Sciences. Educators have permission to
reprint articles for classroom use; other users, please contact editor for reprint
permission. See reprint policy.
About the author: Robert Fletcher, Ph.D., is a Research
Associate at the University of Montana. He received his
doctorate from Iowa State University in Ecology and
Evolutionary Biology in 2003. His interests include habitat
fragmentation and habitat restoration, population biology,
landscape ecology, and statistics. He has done research
throughout much of the United States, including Iowa,
Florida, and Colorado, focusing on conservation issues of
grassland, wetland, and riparian bird communities.
http://avianscience.dbs.umt.edu/about_staff.htm
What are Phosphates ?
Phosphorous is an element which occurs naturally in the environment as phosphorous rock. It is essential to life and is
required by all living cells in order for them to function. One of the most widely used properties of phosphates is their
ability to promote growth of all plant life, hence their widespread use in fertilisers.
Why too much can cause a problem
When excess plant nutrients, especially phorporous, enter our rivers and lakes they increase the amount of nutrients
available for plant growth. A process known as Eutrophication. This causes excessive growth of plants such as algae,
causing what is known as algal bloom and appearing to turn the lake green.
Algal blooms on the surface of the lake shading the plants growing underneath. These plants then die and are
decomposed. This decomposition is carried out by micro organisms who require oxygen in order to live. In decomposing
the plants in the lake the micro organisms require more oxygen than is naturally available and the oxygen levels in the
lake will be used up. This results in a very unhealthy lake incapable of supporting plant and animal life. The lake dies.
How do they enter our rivers and lakes?
The major cause of excess phosphates is from agricultural run- off. Fertilisers are washed off the land, down the streams
and rivers into our lakes. The second major source of phosphates is from industrial waste. Washing your clothes and
other fabrics can add up to 15% of total phosphates.
Citation:
"Aquatic Environment - The Phosphate Problem." Shannon Reginnal Fisheries Board. n.d.. Shannon
Regional Fisheries Board. 7 Oct 2007 <http://www.shannon-fishery-board.ie/aboutus/phosphates.htm>.